题目：
给定一个字符串str,判断是不是整体有效的括号字符串
举例：
str = "()" return true; stre = "()()" return true;
str = "())" return false; str = "()a()" return false;代码：
package com.chenyu.string.cn;public class IsValid {public static void main(String[] args) {String s1 = "()";String s2 = "()(()";String s3 = "()(4)";System.out.println("result1:" + isValid(s1));System.out.println("result2:" + isValid(s2));System.out.println("result3:" + isValid(s3));}public static boolean isValid(String s) {if (s == null || "".equals(s)) {return false;}char[] chars = s.toCharArray();int count = 0;for (int i = 0; i < chars.length; i++) {i
![深入浅出Mybatis系列（八）---mapper映射文件配置之select、resultMap[转]](http://pic.xiahunao.cn/深入浅出Mybatis系列（八）---mapper映射文件配置之select、resultMap[转])
